
The2-ABlabelingkitcontainstwosetsofthefollowingreagents(15samplesperkit)suppliedinglassampoulessealedunderpurenitrogen: 2-Aminobenzamide(2-ABdye) Dimethylsulfoxide(DMSO) Aceticacid Sodiumcyanoborohydrideor2-picolineborane
TrADItional2-AAand2-ABlabellingkitsusesodiumcyanoborohydrideasareducingagentduringglycanlabeling.Thisreagentistoxicsoafumecupboardshouldbeusedduringhandling.ToconformwithemerginghealthandsafetyregulationswearenowreplacingthesewithournewVPglycankitsthatusepicolineboranewhichisasignificantlysaferreductant.
NumberofSamplesOne2-ABlabelingkitcontainsreagentstolabelupto30separateanalyticalsamplesperkit
Dyepurity>99%byHPLC
Molecularweight137
LamBDa-ex320nm
Lambda-em420nm
AmountofSampleFrom25pmolupto25nmolglycanspersample./p>
SuitableSamplesAnypurifiedglycanswithfreereducingterminicanbelabeled.
StructuralIntegrityNodetectable(<2molepercent)lossofsialicacid,fucose,sulfate,orphosphate.
LabelingEfficiencyTypically>85%(dependentonsample).
LabelingSelectivityEssentiallystoichiometriclabeling.
Protocol1. PurifytheglycansLudgerCleanEB10cartidges(LC-EB10-A6)havebeendesignedforpurificationofglycansfromproteins,salts,anddetergents.
2.TransfersampletoreactionvialTheamountofsampleshouldbeintherange100picomoles–50nanomolesforaglycanpoolobtainedfromatypicalglycoprotein.Withasinglepureglycanaslittleas5picomolescanbelabeledanddetectedinsubsequentHPLCanalysis.SuitablereactionvialsincludesmallpolypropylenemicrocentrifugetubesandtubesforPCRwork.
3. DrythesamplesIdeally,samplesshouldbedriedusingacentrifugalevaporator.IfthisisnotpossIBLethenfreezedrying(lyophilization)canbeusedwithcaution(inparticular,ensurethatthesampledriestoasmall,compactmassattheverybottomofthevial).Donotsubjectsamplestohightemperatures(>28°C)orextremesofpHastheseconditionswillresultinacidcatalysedlossofsialicacids(hightemperatures,lowpH)orepimerizationoftheglycanreducingterminus(athighpH).
4.PrepareaDMSO-aceticacidmixtureAdd150μLglacialaceticacidtothevialofDMSOandmixbyPipetteaction.
5.AddthedyeAdd100μLoftheDMSO-aceticacidmixturetoavialofthe2-AB(2-AminobenzamideAcid)dyeandmixuntilthedyeisdissolved.
6.AddthereductantAddthedissolveddyetoavialofsodiumcyanoborohydrideorpicolineboraneandmixbypipetteactionuntilthereductantiscompletelydissolvedtomakethefinallabelingreagent.
7.AddlabelingreagenttosamplesAdd5μLoflabelingreagenttoeachdriedglycansample,capthemicrotube,mixthoroughly.
8.IncubatePlacethereactionvialsinaheatingblock,sandtray,ordryovensetat65°Candincubatefor3hours.Inmostcases,theincubationtimecanbeshortenedto2hoursorextendedupto4hourswithoutsignificantlychangingtheoutcomeofthelabelingreaction.
9.CentrifugeandcoolAftertheincubationperiodremovethesamples,centrifugethemicrotubesbriefly,thenallowthemtocoolcompletelytoroomtemperature.
10.SampleCleanupPost-labelingsamplecleanupisrecommendedtoremoveexcessdyeandotherlabelingreagents.CleanupcanbeachievedusingLudgerCleanT1cartridges(LC-T1-A6)orScartridges(LC-S-A6)
2-ABLabelingReferences
AnumulaKR,DhumeST.Highresolutionandhighsensitivitymethodsforoligosaccharidemappingandcharacterizationbynormalphasehighperformanceliquidchromatographyfollowingderivatizationwithhighlyfluorescentanthranilicacid.GlycoBIOLOGy8685-694(1998)
BiggeJC,PatelTP,BruceJA,GouldingPN,CharlesSM,ParekhRB.Nonselectiveandefficientfluorescentlabelingofglycansusing2-aminobenzamideandanthranilicacid.AnalBiochem230:229-238(1995)
Guile,G.R.;Rudd,P.M.;Wing,D.R.;Prime,S.B.;Dwek,R.A.Arapidandhigh-resolutionhigh-performanceliquidchromatographicmethodforseparatingglycanmixturesandanalyzingoligosaccharideprofilesAnalyticalBiochemistry240:210-226(1996)
Hardy,M.R.‘Glycanlabelingwiththefluorophores2-aminobenzamideandanthranilicacid’in‘TechniquesinGlycobiology’,editedbyTownsend,R.RandHotchkiss,A.T..MarcelDekkerInc,NewYork(1997)
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一般来讲,进行real-time qPCR MasterMix都是2×的浓缩液,只需要加入模板和引物就可以。由于real-time qPCR灵敏度高,所以每个样品至少要做3个平行孔,以防在后面的数据分析中,由于Ct相差较多或者SD太大,无法进行统计分析。通常来讲,反应体系的引 物终浓度为100-400mM;模板如果是总RNA一般是10ng-500,如果cDNA,通常情况下是1ul或者1ul的10倍稀释液,要根据目的基因 的表达丰度进行调整。当然这些都是经验值,在操作过程中,还需要根据所用MasterMix,模板和引物的不同进行优化,达到一个最佳反应体系。在反应体 系配置过程中,有下面几点需要注意:
1. MasterMix不要反复冻融,如果经常使用,最好溶解后放在4度。
2. 更多的配制Mix进行,减少加样误差。最好能在冰上操作。
3. 每管或每孔都要换新枪头!不要连续用同一个枪头加样!
4. 所有成分加完后,离心去除气泡。
5. 每个样品至少3个平行孔。
在分子生物学中,探针是根据碱基互补的原理,用来与特定的DNA片段做杂交以对特定的DNA片段进行检测,如Southern杂交
引物是用来扩增DNA序列的,因为核苷酸必须要连接在3-OH上才能够合成延伸,引物就是用来提供3-OH的。
只要是符合要求的DNA片段都可以用来做探针和引物,引物是用来扩增DNA序列,探针用来与特定的DNA片段做分子杂交的

